Short answers, pulled from the story.
The Zero combined a very low stalling speed, extraordinary range of over 2,600 km, and the ability to out-turn every Allied fighter of the early war period. Its kill ratio in early combat operations reached 12 to 1. Allied pilots who used conventional turning dogfight tactics against it suffered heavy losses.
Chief designer Jiro Horikoshi concluded that the Imperial Japanese Navy's 1937 performance requirements could only be met by making the aircraft as light as possible. Armor and self-sealing tanks were deliberately omitted to save weight, making the Zero more maneuverable and longer-ranged but prone to catching fire when hit.
The Akutan Zero was an A6M2 that crash-landed on Akutan Island in the Aleutians on the 4th of June 1942 after being hit by anti-aircraft fire. Flight Petty Officer Tadayoshi Koga died in the crash. American engineers repaired and tested the aircraft at Naval Air Station North Island, documenting the Zero's strengths and weaknesses in precise technical detail.
Allied pilots learned to avoid turning fights and instead used high-speed diving attacks from altitude, firing a quick burst and climbing away before the Zero could respond. Lieutenant Commander John S. Thach also developed the Thach Weave, a two-fighter tactic first used at the Battle of Midway, in which paired aircraft would turn toward each other to trap a pursuing Zero in the gunsights of the wingman.
Total production was between 10,934 and 11,291 aircraft across all variants, depending on the source. Mitsubishi's Nagoya plant built 3,879 and Nakajima's Ota plant built 6,538, with the remainder being trainer versions built by Hitachi and the Sasebo Naval Air Arsenal. Japan produced more Zeros than any other combat aircraft during the war.
The official Allied code name was "Zeke," assigned by Captain Frank T. McCoy of Nashville, Tennessee, who worked with the Allied Technical Air Intelligence Unit at Eagle Farm Airport in Australia. The name "Zero" remained far more commonly used. Two variants received separate code names: the floatplane version was called "Rufe" and the A6M3-32 variant was initially named "Hap" before being changed to "Hamp" after General Hap Arnold objected.